Flat displays are known in the art and may be realized by one of many techniques such as by employing, for example, liquid crystal, plasma, electroluminescent, and field emission technology. All of these known techniques suffer from a number of inherent limitations which make them unsuitable for many applications. The liquid crystal displays are non-emissive which restricts their use to environments with ambient lighting or in conjunction with an attendant light source. Plasma and electroluminescent displays, while emissive, are not readily implemented as full color displays and further suffer from insufficient light output for bright ambient applications such as in direct sunlight.
Field emission displays provide improved operation over other flat displays. However, field emission displays are known to suffer from arc discharge damage induced through liberation of adsorbed and absorbed contaminants during display operation. Also, known flat field emission displays employ spacers to maintain a nominal faceplate to electron emitter spacing. Spacers disposed between the faceplate and substrate are intrusive and objectionable as they tend to inhibit full utilization of the faceplate area.
Further, known flat field emission displays suffer from a limited capability to withstand outgassing within the evacuated volume which is an integral part of the display.
Accordingly, there exists a need for a flat field emission display which overcomes at least some of these shortcomings of the prior art.
It is one purpose of the present invention to provide a structurally sound image display apparatus which does not employ discrete supporting spacers between the electron emitting layer and the cathodoluminescent layer.
It is another purpose of the present invention to provide an image display apparatus comprised of an evacuated plenum which reduces the effects of outgassing which may occur within the display evacuated regions.
It is yet another purpose of the present invention to provide a flat image display apparatus with an electrostatic ion trap in concert with a getter material to actively control the effects of residual gas contaminants which may be disposed within the interspace aperture, the substrate aperture, and plenum.